|Member(s):||All NEA member countries|
Under the NEA Statute
International Atomic Energy Agency (IAEA)|
|Date of creation:||29 March 2019|
|End of mandate:||29 March 2021|
Mandate (Document reference):
Mandate (Document extract):
Extract of document NEA/CRPPH(2018)4
Radiation exposure to the lens of the eye, above a threshold dose, has been linked to its opacification (or clouding of the lens, which, in its advanced stages, is referred to as a cataract). In order to prevent this effect, dose limits have been defined for the lens of the eye.
On 21 April 2011, the International Commission on Radiological Protection (ICRP) issued a formal statement indicating that tissue reactions for the lens of the eye have dose thresholds that are, or might be, lower than previously considered. This statement indicated the threshold for absorbed dose was now considered to be 0.5 gray. For occupational exposure in planned situations, the ICRP therefore recommended an equivalent dose limit for the lens of the eye of 20 mSv in a year, averaged over defined five-year periods (i.e. 100 mSv/5 years), with no single year exceeding 50 mSv. The ICRP did not change its recommended dose limit for the lens of the eye for members of the public.
In 2012, the ICRP reinforced its recommendation in relation to the dose limit to the lens of the eye when it released ICRP Publication 118, ICRP Statement on Tissue Reactions/Early and Late Effects of Radiation in Normal Tissue and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context.
The IAEA also incorporated these ICRP recommendations into Schedule III of the General Safety Requirements Part 3, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards. Similarly, the new recommendations was incorporated in the European Union legislation with the Council Directive 2013/59/Euratom of 5 December 2013 laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation.
In alignment with the recommendations of the ICRP, some regulators, such as the Canadian Nuclear Safety Commission (CNSC) have proposed to amend the equivalent dose limit for the lens of an eye in their regulations. In response, some stakeholders, e.g nuclear licensees, have identified the proposed revisions to the equivalent dose limit for the lens of an eye as a significant issue. Stakeholder concerns included:
technical issues with the determination of dose to the lens of an eye;
challenges with the appropriateness of the new dose limit based on a review of the scientific evidence of health effects; more research might need to be undertaken before dose limits are changed;
claims that the change in the dose limit is not warranted, considering that the health effect (cataracts) is regarded as easily treatable;
significant financial and administrative burden with the proposed change and the associated impact on their operation: in particular, for those exposure situations with non-uniform fields, where the lens of an eye dose could be the limiting exposure for workers.
To address these concerns, some regulators, e.g. the CNSC, and international fora, i.e. the International Radiation Protection Association (IRPA) and the Information System on Occupational Exposure (ISOE) have undertaken a series of initiatives to address these concerns. The Committee on Radiological Protection and Public Health (CRPPH) has recognised that there are aspects that regulators and stakeholders worldwide could benefit in learning from other countries that already implemented the ICRP-recommended equivalent dose limit for the lens of the eye, to ensure that additional efforts are strategic and optimised. There are a number of resources available regarding perspectives on the science behind the ICRP’s recommendation and guidance on hazard/risk assessments; however, the sharing of experiences on the practicality of implementing the recommendation, including successes and challenges, is an aspect that may benefit regulators and stakeholders.
The main objective of the EGDLE is to provide an opportunity for regulators and stakeholders, e.g. nuclear licensees, to share lessons learned (both successes and challenges) in the practical implementation of the ICRP’s recommended equivalent dose limit for the lens of the eye for occupational exposures.
The Expert Group on the Dose Limit for the Lens of the Eye (EGDLE) supports the CRPPH mandate, which states: “the Committee shall … promote international collaboration on specific radiological protection and radiation-related public health topics of interest to the NEA member countries in the framework of the NEA Strategic Plan” [NEA/NE(2017)13].
Methods of Working
The EGDLE membership shall be composed of nominated NEA Member Countries. Members may bring experts from their organisations to enrich the exchanges between the regulatory bodies.
Periodically, the EGDLE will report to the CRPPH and assist the Committee with its work.
The working methodology of the EGDLE will be based on surveys, followed by meetings and exchanges of information such as technical notes, communication products and reports.
The EGDLE will interact, as appropriate, with other NEA standing technical committees, as well as with national and international organisations and fora, such as the ICRP, IAEA, European Commission, IRPA, and ISOE, in order to apply the right expertise to the right issues and avoid duplicating efforts.
The deliverables of the EGDLE will include:
A report which summarises the practical experiences of regulators and stakeholders worldwide for implementing the ICRP’s recommended equivalent dose limit for the lens of the eye for occupational exposure, including successes and challenges to the approaches; and
A network established to maintain dialogue and information exchange.
 The ICRP Publication 118 is available at: www.icrp.org/publication.asp?id=ICRP%20Publication%20118
 The International Basic Safety Standards are available at: www-pub.iaea.org/MTCD/Publications/PDF/Pub1578_web-57265295.pdf.
 The Council Directive 2013/59/Euratom is available at: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32013L0059.